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4 years ago

Why do most planets orbit in a disc

Physics

2 answers:

Vesnalui [34]4 years ago

6 0

are there any answer choices

Maru [420]4 years ago

3 0

Have a great dayyyyyyyy!

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A ball is dropped from rest from a height h above the ground. another ball is thrown vertically upwards from the ground at the i

Darya [45]

The position of the first ball is

$y_1=h-\dfrac g2t^2$

while the position of the second ball, thrown with initial velocity $v$ , is

$y_2=vt-\dfrac g2t^2$

The time it takes for the first ball to reach the halfway point satisfies

$\dfrac h2=h-\dfrac g2t^2$

$\implies\dfrac h2=\dfrac g2t^2$

$\implies t=\sqrt{\dfrac hg}$

We want the second ball to reach the same height at the same time, so that

$\dfrac h2=v\sqrt{\dfrac hg}-\dfrac g2\left(\sqrt{\dfrac hg}\right)^2$

$\implies h=2v\sqrt{\dfrac hg}-g\left(\dfrac hg\right)$

$\implies h=v\sqrt{\dfrac hg}$

$\implies v=\sqrt{hg}$

8 0

4 years ago

A frictionless pendulum is made with a bob of mass 19.7 kg. The bob is held at height = 0.934 meter above the bottom of its traj

Alika [10]

Answer:

265 J

Explanation:

$Energy=PE+KE=mgh+ 0.5mv^{2}$ where KE is kinetic energy, PE is potential energy, m is the mass of an object, v is the speed, h is the height and g is acceleration due to gravity.

Substituting 19.7 Kg for mass, 0.934 for h, 2.93 for v and 9.81 for g then

$Energy=19.7(9.81*0.934+0.5*2.93^{2})=265.063303\approx 265 J$

4 0

3 years ago

Please help me with this question, especially the angle part. I have solved the initial velocity already. I don't know what to d

Helga [31]

I think you almost got it.

At the top, the velocity only has horizontal component, so v=12 m/s is v_x, which is v*cos(theta), because v_x is constant, so the same when it was launched or now.

With the value of the initial speed (28 m/s, which is the total speed), you can set

v_x = v * cos( theta ) ---> 12 = 28*cos(theta) --> cos(theta)=12/28=3/7

or theta = 64.62 deg, it is D. Think about it. I hope you see it.

5 0

3 years ago

Which Sentence Describes A Physical Property

Alina [70]

The answer is (a).

Golf balls have a higher density than water hence sink to the bottom.

8 0

4 years ago

A Porsche challenges a Honda to a 400-m race. Because the Porsche's acceleration of 3.5 m/s² is larger than the Honda's 3.0 m/s²

GarryVolchara [31]

Answer: The Porsche Wins. Arrives 19secs earlier before the Honda.

Explanation: The head start of 1secs corresponded with the difference in acceleration {3.5m/s² - 3m/s²}=0.5m/s²

Using the first equation of motion we obtain the velocity which correspond to this acceleration (0.5m/s²) and time of 1secs where initial velocity u = 0

V = u + at

V= 0 + at

V = 0.5 * 1 = 0.5m/s

Now let find the velocity of each of the car.

If V. a

0.5m/s 0.5m/s²

........m/s. 3.5m/s²

Velocity of porche Vp

= (3.5/0.5) * 0.5 = 3.5 m/s

Also if. V. a

0.5m/s. 0.5m/s²

.....m/s. 3 m/s²

Velocity of Honda Vh

= {3/0.5} * 0.5 = 3m/s

So let's find the time t taken by both cars to cover the distance of 400m

Recall,

Velocity = distance/time

Time t = distance/velocity

For Porche, t = 400/3.5 =114.29secs

For Honda, t = 400/3 = 133.33secs

Looking critically, we noticed that Porche car took shorter time.

The difference In time is

= (133.33 - 114.29)secs = 19.04secs

3 0

3 years ago